Procedural texture of random square clusters
If you take a Voronoi Texture's Randomness parameter all the way to 0 it generates squares like you want.

You can take the Color output into a Noise Texture like you suspected and generate lots of different outputs.  What I did here was put a Color Ramp on the other side set to Constant to isolate groups of these squares to use as a mask for whatever you want.

But you can imagine animating some of these values and generating any number of visualizations.